varicella vs chickenpox

varicella and chickenpox both are nouns.

Word	Noun	Adjective	Verb	Adverb
varicella	Yes	No	No	No
chickenpox	Yes	No	No	No

As nouns, varicella and chickenpox are synonyms defined as:

varicella and chickenpox: an acute contagious disease caused by herpes varicella zoster virus; causes a rash of vesicles on the face and body

varicella (noun)	chickenpox (noun)
an acute contagious disease caused by herpes varicella zoster virus; causes a rash of vesicles on the face and body	an acute contagious disease caused by herpes varicella zoster virus; causes a rash of vesicles on the face and body